Stem winding mechanism for watches



April 17, 1928. 1,666,774

H. COLOMB STEM WINDING MECHANISM FOR WATCHES Filed Aug. 11, 1924 Patented Apr. 17, 1928.

HENRI'COLOMB, OF TAVANNES, SWITZERLAND.

Application filed August 11, 1924, Serial No.

This invention relates to oblong or rec tangular-shaped thinwatch movements such as are generally used in wrist watches, and is designed to render possible the utilization of the Waste space heretofore existing in one end of such movement by filling the same with a mainspring of large diameter, the increased power of which spring contributes to the more satisfactory operation of the movement.

' Heretofore it has not been possible to use such large mainsprings because when the said large spring has been arranged for winding from the usual stem-winding mechanism located at the middle of one of the longer sides of the movement and having a shaft coincident with the minor axis of the movement and of the containing case, the contrate-wheel of said stem-windin mechanism meshing directly with the mainspring ratchet wheel, any enlargement of the spring barrel has caused its circumference to approach too near to the stone bearing of the center wheel axis or hand supporting mechanism located at the center of the movement, unless said barrel has been moved away therefrom; and, if this moving away of the spring itself has been attempted it has required making the driving gear of the stem-winding mechanism, which meshes with the ratchet gear of the mainspring, of such large diameter as to result in the Weakening of the supporting bridge by the cutting away of the larger recess then re uired for said gear, and in otherwise inter ering with other parts of the movement.

I have discovered that these difliculties can be overcome by interposing a relatively small idler gear wheel in said train of winding mechanism, whereby, also, the primary gear wheel, or contrate-wheel, thereof may be made smaller, instead of larger, the center of the spring barrel moved farther away into the waste space in one end of the movement, and a spring and barrel of larger diameter employed, all without the latter approaching too near to the center of the movement, at which latter point the handsupporting shaft and driving gearing must be mounted.

The best form of apparatus at present known to me for carrying out my invention, togetherwith one modification thereof, is

STEM WINDING MECHANISM FOR WATCHES.

731,537, and in Switzerland August 24, 1928.

illustrated in the accompanying sheet of drawings in which,

Fig. l is a plan view of an old form of watch movement on which my invention is an improvement.

Fig. 2 plan view of a watch movement embodying one form of my invention, parts being broken away.

Fig. 3 is a similar view of a modification.

Fig. 4 is a longitudinal cross section of theform shown in Fig. 3, and

,Fig. 5 is a detail view of the contrate wheel and portion of the stem winding gearing, taken on the line 55 of Fig. 3.

Throughout the drawings like reference characters indicate like parts.

Referring to Fig. 1, b is the barrel of the mainspring, 1' is the winding ratchet ear wheel therefor, and c the contrate-whee by which it is actuated from the usual stemwinding and setting mechanism. a2m is the major axis of the movement and g -y the minor axis. It is necessary to put the hand-supporting mechanism at the intersection a of these axes and provide a bearing stone therefor and it will be evident that the circumference of the spring barrel 1) already closely approaches this point so that any further increase of diameter of said barrel is impossible without moving the center of said barrel further away from the center of the contrate-wheel, and that if this is done the center of said barrel mustbe placed nearer the major axis wa: so that its circumference will not interfere with the bridge fastening screw 8, which arrangement would result, in turn, in the circumference of the enlarged barrel approaching still nearer the movement center a. It is also evident that if the diameter of contratewheel 0 were further enlarged to enable it to mesh with a more remote ratchet Wheel '1', this would require the bridges to be cut away too much and also interfere with other parts of the movement.

Referring to Fig. 2, these difiiculties are avoided by inserting the idler gear a between the contrate-wheel c and the ratchet wheel 1'. As a result the spring barrelb may be much enlarged, and its center shifted diagonally toward the end of the movement and toward the major axis a:-:v, without causing the barrel periphery to approach any closer to the movement center 2-, where the stone for the hand supporting mechanism. is to be located. Also the contratewheel 0 may then be made smaller, instead of being increased in diameter.

in th form. shown in Figs. 3 and 4 the same result is accomplished by moving over the contrate-wheel c and actuating it by gearing p, p -irom the stem-winding shaft. This latter arrangement is rendered possible by placing the gear 7) on a shaft located in a plane nearer to that of the contrate-wheel 0 than that in which the shaft oi? the stemwindino' apparatus on which gear 3) is mounted, is located, that gear 79 will clear the contratewhecl although it partly underlies said wheel. 'lhis conduces to greater compactness of the winding mechanism. The shattoi said gear wheel ya is journalled on the bridge carrying the contrate-wheel. This arrangei'ncnt is clearly shown in Fig. 4.

Having described my invention I claim:

1. In an oblong watch movement adapted to have the mechanism forsupporting the hands located at the center thereof, a stem winding and setting apparatus comprising a bottom plate coextensive with the movement, a bridge covering one end of the plate and extending past its shorter middle axis, a winding and setting stem the axis of which coincides with the minor axis of said movement, a mainspring journalled between said bridge and plate, and a ratchet wheel on the outside of the bridge concentric with. said 's rin for windin 11) said main s rin D b a.

the combination, with said above described apparatus, of a train of gearing from said stem-winding. apparatus to said ratchet wheel con'i'prising two gear wheels of relatively small diameter, atleast one of which is outside the bridge and overlaps said. barrel and both supported from said bridge; whereby said mainspring may be located in one end of said oblong movement and given a large diameter without touching the hearing stone or axis of said hand-supporting mechanism.

2. A combinationsuch as defined in claim 1 in which that one of said relatively small gears in mesh with said ratchet wheel is a contra-te wheel, and the other gear wheel meshing therewith is mounted-on a shaft journalled in aplane parallel, and nearer, to said contrate wheel than is that in which said stem-winding shaft is located, whereby compactness of said winding mechanism is secured.

In testimony whereof I aifix my signature.

HENRI COLOMB; 

